introduction: response to morphine and role of nitric oxide (no) on expression of morphine response has been studied in vertebrates. but, little evidence is provided in the matter in earlier invertebrates. this investigation for the first time evaluated the effect of no on expression of morphine potency in paramecium caudatum. methods: animal after isolation from natural media and specific iden...

The periaqueductal gray (PAG) has been reported to be a location for opioid regulation of pain and a potential site for behavioral selection in females. Opioid-mediated behavioral and physiological responses differ according to the activity of opioid receptor subtypes. The present study investigated the effects of the peripheral injection of the kappa-opioid receptor agonist U69593 into the dor...

Osteoarthritis (OA) is a chronic joint disorder whose principal symptom is chronic pain. Current analgesics are inadequate and the mechanisms contributing to this pain are poorly understood but likely to include both local joint changes and central consequences. These studies used monoamine receptor agents combined with behavioral studies and single-unit dorsal horn recordings to examine whethe...

We have previously shown that the balance of electrically evoked descending brainstem control of spinal nociceptive reflexes undergoes a switch from excitation to inhibition in preadolescent rats. Here we show that the same developmental switch occurs when μ-opioid receptor agonists are microinjected into the rostroventral medulla (RVM). Microinjections of the μ-opioid receptor agonist [D-Ala(2...

BACKGROUND Recent studies have revealed that N2O exerts its antinociceptive effect by inducing opioid peptide release in the brain stem, thereby activating the descending noradrenergic inhibitory neurons, which modulate pain processing in the spinal cord. However, the precise neuronal pathways that mediate these events remain to be determined. METHODS Using immunohistochemical and behavioral ...

ziziphora tenuior has been used in iranian folk medicine as an analgesic and for treament of digestive diseases.this study was designed to investigate the antinociceptive effects of hydroalcoholic extract of z. tenuior on visceral pain and its possible involvement in opioidergic and serotoninergic systems in male albino n-mri mice. antinociceptive effect of was determined by writhing test as a ...

Annotation. The problem of effective and safe treatment pain syndromes is a priority area modern medicine, since syndrome often accompanied by economic costs, drop in labor productivity an increase the risk other diseases. derivative 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxamide (compound NI-9) has shown significant analgesic effect various models syndromes. aim this work was to exper...

Several studies have demonstrated the involvement of the central nucleus of the amygdala (CEA) in the modulation of defensive behavior and in antinociceptive regulation. In a previous study, we demonstrated the existence of a cholinergic-opioidergic interaction in the CEA, modulating the defensive response of tonic immobility in guinea pigs. In the present study, we investigated a similar inter...